Apparatus for making pipes from fiber pulp

ABSTRACT

An apparatus for making pipes from a pulp which contains fiber material and a binder comprises a pulp feeder, couch-roll means for couching pulp from said feeder, a horizontal breast roll spaced from the couch-roll means, a mandrel detachably supported on the top of said breast roll, pressure-roll means arranged to urge said mandrel against said breast roll, and an endless felt blanket, which is trained over said couch-roll means and is mounted on support means to pass between said pressure-roll means and said mandrel and to pass from said pressure-roll means extends back to said couch-roll means out of contact with said breast roll. The blanket transfers said pulp in the form of a web from said couch-roll means to said mandrel. The web is wound around the mandrel in a tubular form to form the desired pipes.

United States Patent [72] Inventor Johann Schoggl St. Rolten, Niederosterrelch, Austria [21] Appl. No. 795,208 [22] Filed Jan. 30, 1969 [45] Patented Nov. 9, 1971 [73] Assignee J. M. Voith AG Lower Austria, Austria [32] Priority Jan. 30, 1968 [33] Austria [3 I 1 A 920/68 [54] APPARATUS FOR MAKING PIPES FROM FIBER PULP 21 Claims, 11 Drawing Figs.

[52] US. Cl 162/284, [8/4 B, 18/19 TM, 25/30, 162/118 [51] 1nt.Cl 1331c H08 [50] Field of Search 162/284,

118, 283; 242/65, 66; 25/30 A; 18/4 B, 19 TM [56] References Cited UNITED STATES PATENTS 3,197,361 7/1965 Schneider 162/284 Primary Examiner-S. Leon Bashore Assistant Examiner-Richard H. Tushin Attorneyl(arl F. Ross ABSTRACT: An apparatus for making pipes from a pulp which contains fiber material and a binder comprises a pulp feeder, couch-roll means for couching pulp from said feeder, a horizontal breast roll spaced from the couch-roll means, a mandrel detachably supported on the top of said breast roll, pressure-roll means arranged to urge said mandrel against said breast roll, and an endless felt blanket, which is trained over said couch-roll means and is mounted on support means to pass between said pressure-roll means and said mandrel and to pass from said pressure-roll means extends back to said couchroll means out of contact with said breast roll. The blanket transfers said pulp in the form of a web from said couch-roll means to said mandrel. The web is wound around the mandrel in a tubular form to form the desired pipes.

APPARATUS FOR MAKING PIPES FROM FIBER PULP Known machines for making pipes of asbestos cement comprise upper and lower felt blankets and operate in accordance with a full-width winding process. A rotating screening drum has a width which corresponds to the length of the pipe to be made and is immersed in the fiber pulp. On this drum, a fiber material web is formed in that the water permeates the screening drum and the fiber pulp is retained on the screen surface. The water is drained from the interior of the screening drum. The couch roll urges an endless felt blanket against the top of the screening drum so that the web is transferred to the felt blanket. This felt blanket is trained as a lower felt blanket around a breast roll and subsequently around tensioning means and through washing means. Dewatering means are incorporated adjacent to the path of the lower felt blanket and serve to dewater the felt blanket and the web lying thereon.

The mandrel is applied to the breast roll at the top thereof. The mandrel consists generally of a cylindrical member made of steel or cast iron and having a length which slightly exceeds that of the pipe to be made and has a surface which is smooth or roughened, e.g., knurled. Under the pressure applied by the mandrel to the breast roll, the web is couched and wound onto the mandrel. The winding operation is continued until the desired wall thickness of the pipe has been reached. The operation is then interrupted for a short time, the wound mandrel is removed and a new mandrel is inserted. The operation can then be repeated.

During the winding operation, pressure rolls are urged against the mandrel. The so-called upper felt is trained over these pressure rolls, which serve further to consolidate the web and to extract additional water from the raw material by means of the felt blanket. The upper felt blanket is also trained over tensioning means, through washing means and over dewatering means.

Hearing the name of its inventor, this process is known as a Mazza process. It has the disadvantage that the lower felt blanket must be guided by deflecting rolls from the couch roll to the breast roll and required much space, which is needed for the access to the machine and mainly for a replacement of the mandrel. The two felt blankets render the operation more expensive because they are subject to heavy wear, particularly when processing asbestos cement. High-vacuum suctions means are used to dewater the fiber web on the lower felt blankets and result in a strong wear of the felt.

Another apparatus has been disclosed which serves to manufacture asbestos cement plates from a thin asbestos cement pulp by means of screening cylinders, which take up an asbestos cement film from the pulp and transfer said film onto a felt blanket, which transfers the partly dewatered film of asbestos cement onto a size-determining roll. In this apparatus, the output of the known plate-making machine having three screening cylinders is allegedly doubled, approximately. in that the size-determining roll has two endless felt blankets associated with it, which are separately forced against the size-determining roll at different points and are trained around separate groups of screening cylinders. In this apparatus, the web is supplied from above to the mandrel, The machine is complicated in design and the space between the couch roll and the mandrel is obstructed.

In another known machine having upper and lower felt blankets, the mandrels are fed with the web by the lower felt blanket and are automatically moved to their working position by a chain drive having a revolving endless chain. This machine is expensive, too. The space between the breast and couch rolls is considerably obstructed by the chain drive.

It is an object of the invention to provide an apparatus for making pipes from a mixture which contains fiber material, such as asbestos, and a binder, e.g., of hydraulic nature, with the aid of a single endless felt blanket which carries the pulp and which is trained around at least one couch roll, which couches the pulp from a feeder, e.g., a screening drum, and around at least one pressure roll, which forces the felt blanket and the web thereon from above against the mandrel, which is supported by a breast roll. In an apparatus of this nature, which also uses only a single felt blanket, it is known to guide the felt blanket in such a manner that with reference to the couch roll it is used first as an upper felt blanket and then as a lower felt blanket. When the felt blanket has left the pressure rolls adjacent to the breast roll, the felt blanket moves around a reversing roll and then back to the breast roll, from which the felt blanket returns to the couch roll. This apparatus has the disadvantage that the mandrel is accessible only from one side rather than from both sides. As access from both sides would be desirable to simplify the feeding of the pipe-making machine with mandrels and to save space. This can be accomplished in that, according to the invention, the felt blanket returns from the pressure roll or rolls to the couch roll or rolls without contacting the breast roll. In a pipe-making machine according to the invention, there are free spaces before and behind the mandrel in operating position so that there is adequate space for accommodating the means for feeding the mandrels.

Another known machine comprises only a lower felt blanket. Whereas this machine avoids the use of two felt blankets, it does not afford an improved access.

The invention will be explained more fully hereinafter with reference to embodiments shown by way of example in the drawing, in which FIG. 1 is a diagrammatic view showing a pipemaking apparatus according to the invention,

FIG. 2 shows a detail of FIG. 1 on a larger scale.

FIG. 3 shows another detail of FIG. 1, also on a larger scale.

FIG. 3a is a sectional view taken on line IIIaIIIa in FIG. 3.

FIG. 4 shows another detail of FIG. 1.

FIG. Sis a sectional view taken on line vV in FIG. 4.

FIG. 6 is an axial sectional view showing a modification of the detail shown in FIGS. 4 and 5.

FIG. 7 is a sectional view taken on line VIIVII in FIG. 6.

FIG. 8 is a longitudinal sectional view showing another embodiment of the detail shown in FIGS. 4 and 5.

FIG. 9 is a sectional view taken on line lX-IX in FIG. 8 and FIG. 10 is a view similar to FIG. I and shows a detail of a modification of FIG. 1.

With reference to the drawing, a horizontal screening cylinder 1 is rotatably mounted in 126 trough 100, which contains the fiber pulp. A vacuum couch roll 3-9 (parallel to the screening cylinder, shown in more detail in FIGS. 3 and 3a takes dewatered pulp in the form of a thin web from the screening cylinder 1 and transfers said web to the felt blanket 2. This felt blanket 2 moves in the machines as an upper felt, which carries the web, over a guide roll 10 (parallel to the couch roll), a control roll 11 rotatable about shaft 102, which is displaceable in the direction of the arrow A by hydraulic piston-cylinder units 101, and further guide rolls 12 and 14, to pressure rolls 16 (parallel) to the couch roll, where the pipe is formed in a fullwidth winding process, which has been explained hereinbefore. By the two hydraulic piston-cylinder units 101, the control-roll shaft 102 can be moved to a position in which the axis includes an angle differing from with the direction of movement of the felt blanket.

When the web has been transferred to a mandrel 16' adjacent to the pressure rolls 16, the felt blanket 2 is moved over guide rolls 18, 20, 21 and 22, a compensating roll 23, further guide rolls 24 and 25, a drive roll 26, and a tension roll 27 back to the couch roll 3-9 without contacting the breast roll. The drive roll 26 is adapted to be driven by a motor and gear unit, not shown. The guide roll 21 is disposed in a trough 21', in which the felt blanket 2 is washed. For washing the felt, a plurality of high-pressure spraypipes 103 are provided, which direct jets 104 against the felt blanket 2. The trough 21' also includes one or more felt heaters 21'', which can be caused to resolve by drive means which are not shown. A so-called washing vacuum unit 28 is disposed between the tension roll 27 and the couch roll 39. The blanket lies above a horizontal plane which includes the axis of the mandrel.

The pressure car base 34 associated with the pressure rolls 16 is guided by stationary guide bars 39 between stationary bearing plates 40, which are disposed laterally of the machine, and is connected by piston rods 43 to pressure cylinders 41, which are secured to the pressure car top 42. During the winding operation, the pressure bar base 34 is moved upwardly under the action of the pressure cylinders 41 as the wall thickness of the pipe being wound on the mandrel 16' increases. ln dependence on the diameter of the mandrels 16' which are used for the manufacture of a series of equal pipes, the pressure car top 42 is moved to a predetermined level. Positioning cylinders 44 are provided for this purpose and are secured in brackets. The pressure car top 42 is secured to the piston rods 46 of said cylinders. The pressure car top is adjusted when the pressure car base 34 is lowered onto the empty mandrel 16. To ensure that the pressure cars are moved uniformly up and down, a parallel motion is provided, which consists ofa connecting shaft 50, gears 49, bearing holders 48 and racks 47.

The compensating roll 23 serves to maintain the tension of the felt blanket 2 constant when the position of the pressure car is changed. In accordance with FIG. 2, the compensating roll 23 is coupled by a two-armed lever 30 to the pressure car top 34. The lever 30 is pivoted to a stationary bearing 29, which is disposed approximately at the center of the lever. The lever 30 carries at each end a lever 31-33 or 35-37, which is adjustable in length. These levers are pivoted to the compensating rolls 23 and the pressure car base 34. The lever 31-33 consists of three parts, namely, a link 31, which is pivoted to the lever 30, a bearing holder 33, which is pivoted to the pressure car base 34, and an adjusting nut 32, which connects the link 31 to the bearing holder 33. The lever 35-37 is similarly designed. This lever consists also ofa link 35, which is pivoted to the end of the lever 30, a bearing holder 37 for the compensating roll 23, and an adjusting nut, which connects the link 35 to the bearing holder 37. The bearing holder 37 for the compensating roll 23 is slidably mounted by a sliding block 38 in a fixed, straight guide 105.

From the position shown in solid lines, the tension roll 27 (FIG. 1) can be moved by the distance s toward the position shown in broken lines. The tension roll serves to adjust the felt blanket tension to a fixed value in dependence on the quality of the felt which is available, and to thread the felt blanket 2 into the machine.

In FIGS. 3 and 3a the vacuum couch roll 13-9 is shown in more detail. The couch roll has a perforated peripheral surface. A vacuum chamber 3 is disposed in the interior of the couch roll and extends around a portion a of the periphery of the roll and has side edges which are sealed by sealing strips 7 against the inside peripheral surface of the roll. A spraypipe 9 extends inside the couch roll in the longitudinal direction thereof and serves to clean the bores 106, 107 in the peripheral surface of the couch roll. The pipe 9 can be supplied with water continuously or intermittently by a means 109a which is connected to the spraypipe by a pipe 10% and value l09c and by a conduit 109, which is bored in the journal 108. The fixed parts of the couch roll, namely, the vacuum chamber 3 and the spraypipe 9, and are so incorporated in the machine that the spraypipe 9 is disposed in that length portion of the couch roll which is not contacted by the felt blanket 2. Gutters 13' shown in FIG. 1 are provided to prevent a moistening of the felt blanket 2 by water jets which extend outwardly by the bores 106, 107 of the couch roll. Gutters 13 provided inside the couch roll limit the sump formed by the water, which has been issued from the spraypipe 9, The vacuum chamber 3 is drained by a bore 110, which is formed in the second journal 3 of the vacuum couch roll. The shell of the vacuum couch roll is supported on the journals 108 and 3 by taper roller bearings 111 and 112. The space which contains the taper roller bearings 111 and 112 is closed towards the outside by bearing covers 6.

The main advantages of the vacuum couch roll are the fact that the transfer of pulp from the screening cylinder is promoted by the vacuum and couch action, a simultaneous dewatering of the web and the consolidation of the web by the additional vacuum action so that even thick webs cannot fall down as they move around the vacuum couch roll. Such falling-down of the web would interfere with the production.

The pressure which is applied by the pressure rolls 16 to the mandrel 16 or the web thereon is transmitted to the breast roll 62, where it produces a high pressure along a line. For this reason, the breast roll 62 which is horizontal as shown in FIG. 1, is provided with a cover 61, e.g., of plastic material, rubber or the like (FIGS. 4 and 5). The water which has been squeezed out flows off over the breast roll 62. To clean the breast roll 62 so as to remove adhering particles of the web material, and to strip the water from the breast roll, the periphery of the breast roll 62 is contacted by a doctor 68. A spraypipe 63 may precede the doctor in the direction of movement ofthe breast roll 62. The jets from the spraypipe impinge on the periphery of the breast roll 62 and assist in cleaning the breast roll. The cover of the breast roll 62 may consist of a tubular screen of plastics material. This screen may be peripherally movable relative to the breast roll. The screen of plastic material has cavities, which facilitate the removal of the water that has been squeezed out. The water can be blown out or may be discharged through the roll itself if the latter consists ofa screen roll, as is shown in FIGS. 6 to 9. In the embodiment shown in FIGS. 8 and 9, the inside space of the screening roll 62 can be connected to a vacuum source 62a In an apparatus according to the invention, a specially designed device may be used to feed the mandrels to the breast roll. With the aid of that device, the introduction of the empty mandrel, the winding of the web, the calendering of the web and the extraction of the mandrel are performed in four stations. When the winding operation has been terminated, three mandrels are advanced each by a one station. When the mandrel has been extracted, the feeder performs an empty stroke to the next preceding station. FIG. 1 shows by way of example also such a feeder.

The mandrels are shown at A, B, C and D in the ready position, winding position, calendering position and extracting position. The mandrel feeder consists of a car, which has a base 51 that is movable along rails 60 on rollers 112, which are mounted in pillow blocks 53 secured to the base. The car top 56 is adapted to be lifted and lowered relative to the car base by jacks consisting each of a cylinder 55, which is secured to the car base, and a piston, which carries the car top. The car top is guided in longitudinal guides 54, which consist of circular-section guides. Mounting flanges 59 are secured to the end of the car base 51 and engaged by a piston rod 58, the axis of which extends parallel to the rails 60 and which is reciprocably guided in a cylinder 57. The piston rod 58 is operable to move the car along the rails 60 when the cylinder 57 is supplied with a fluid under pressure and exhausted at the same time though conduits which are not shown.

When winding of an asbestos cement pipe has been completed, the feeder car top 56 is lifted by the lifting cylinders 55 so that the mandrel in position of readiness A is lifted from the returning rollers 67, the asbestos cement pipe has just been completely wound in the winding position B is lifted from the breast roll, and the asbestos cement pipe which is in calendering position C is lifted from the calendering rolls. By means of the piston rod 58, the feeder car base is moved to its forward end position. The car top 56 is lowered so that the empty mandrel is deposited on the breast roll 62, the asbestos cement pipe which has just been wound is deposited on the calender rolls 70, and the previously calendered asbestos cement pipe is deposited on the extracting trough or on the inclined runway 69. It will depend on the arrangement of the plant which of these two alternatives will be adopted. In the former case, where a short cycle is used, the mandrel is extracted immediately after the winding operation. In the latter case, the mandrel is not extracted until a preliminary setting time has expired. By means ofthe piston rod 58, the feeder car is returned to its initial rear and position.

FIG. shows a detail of an embodiment comprising two screening drums 1, each of which is disposed in a trough 100, and with two couch rolls 3-9, over which the felt blanket 2 is trained. The other means are the same as those shown in FlG. 1.

What is claimed is:

1. Apparatus for making pipes from a pulp which contains fiber material and a binder, said apparatus comprising a pulp feeder,

couch-roll means for couching a pulp web from said feeder,

a horizontal breast roll, spaced from said couch-roll means a mandrel detachably supported on top of said breast roll,

pressure-roll means arranged to urge said mandrel against said breast roll, means to move said pressure-roll means toward and away from said mandrel,

an endless felt blanket for transferring said pulp from said couch-roll means to said mandrel, said felt blanket being trained over said couch-roll means and mounted on support means for transferring said pulp web from said couch-roll means to said mandrel, said felt blanket passing between said pressure-roll means and said mandrel in order that said web be wound on said mandrel in tubular form, said blanket thereafter extending back to said couch-roll means, said felt blanket being out of contact with said breast roll.

2. Apparatus as set forth in claim 1, in which said pulp feeder comprises a screening drum.

3. Apparatus as set forth in claim 1, in which said felt blanket extends from said pressure-roll means back to said couchroll means above a horizontal plane which includes the axis of said mandrel.

4. Apparatus as set forth in claim 1, in which said pressure-roll means comprises a plurality of pressure rolls,

said pressure rolls are mounted in a pressure car,

said support means including a compensating roll to compensate, for the variation of the tension of said felt blanket resulting from a movement of said car,

said compensating roll being connected to said pressure car by lever means, said lever means comprise a compensating lever and a connecting lever of adjustable length pivoted to one end of said compensating lever and to one of said parts consisting of said pressure car and said compensating roll, and

said compensating lever is pivotally mounted in a stationary bearing intermediate its length.

5. Apparatus as set forth in claim 4, in which said levers means comprises a connecting lever of adjustable length pivoted to the other end of said compensating lever and to the other of said parts.

6. Apparatus as set forth in claim 1, in which said support means includes a tension roll for tensioning said felt blanket and pressure-fluid-operable means controlling the tension applied to the felt blanket by said tension roll.

7. Apparatus as set forth in claim 1, in which said couch-roll means comprise a vacuum couch roll,

said vacuum couch roll comprising a stationary hollow shaft for discharging air and water, an outer screening shell rotatably mounted on said shaft, means defining inside said shell a vacuum chamber around part of the inside periphery of said shell, and means for applying a vacuum to said vacuum chamber.

8. Apparatus as set forth in claim 7, in which said blanket contacts said vacuum couch roll only in part of the periphery thereof and a spraypipe is disposed adjacent to another part of the periphery of said vacuum couch roll and means to supply said spraypipe with liquid to clean said vacuum couch roll.

9. Apparatus as set forth in claim 8, which comprises means for intermittently supplying said spraypipe with liquid.

10. Apparatus as set forth in claim, 8 in which said spraf pilge extends outside said vacuum couch roll.

1 pparatus as set forth In claim 8, in which said spraypipe extends inside said vacuum couch roll.

12. Apparatus as set forth in claim 8, which comprises gutters disposed inside said vacuum couch roll and serving to collect and discharge said liquid.

13. Apparatus as set forth in claim 8, which comprises gutters disposed outside said vacuum couch roll and serving to collect and discharge said liquid.

14. Apparatus as set forth in claim 1, which comprises a covering on said breast roll.

15. apparatus as set forth in claim 14, in which said covering consists of plastic material.

16. Apparatus set forth in claim 14, in which said covering consists of rubber.

17. Apparatus as set forth in claim 14, in which said covering consists ofa tubular screen of plastic material.

18. Apparatus as set forth in claim 17, in which said breast roll comprises a body and said screen surrounds said body and is peripherally movable relative thereto.

19. Apparatus as set forth in claim 1, in which said breast roll consists of a screening roll.

20. Apparatus as set forth in claim 19, which comprises means for applying subatmospheric pressure to the interior of said breast roll.

21. Apparatus as set forth in claim 1, which comprises a mandrel-depositing station,

a mandrel-winding station comprising said pressure roll means and said breast roll,

a calendering station,

a mandrel-extracting station, and

a mandrel-feeding car, which is movable between said four stations,

said mandrel-depositing station comprising means for depositing a mandrel on said car,

said calendering station comprising mean for calendering said web on a mandrel carried by said car,

said mandrel-extracting station comprising means for extracting a mandrel carried by said car from said web wound in tabular form on said mandrel,

means for advancing said car by one station when a mandrel has been sufficiently wound with said web in said mandrel-winding station, and for moving said car back by one station when said mandrel has been extracted from said web in said mandrel-extracting station. 

2. Apparatus as set forth in claim 1, in which said pulp feeder comprises a screening drum.
 3. Apparatus as set forth in claim 1, in which said felt blanket extends from said pressure-roll means back to said couch-roll means above a horizontal plane which includes the axis of said mandrel.
 4. Apparatus as set forth in claim 1, in which said pressure-roll means comprise a plurality of pressure rolls, said pressure rolls are mounted in a pressure car, said support means including a compensating roll to compensate for the variation of the tension of said felt blanket resulting from a movement of said car, said compensating roll being connected to said pressure car by lever means, said lever means comprise a compensating lever and a connecting lever of adjustable length pivoted to one end of said compensating lever and to one of said parts consisting of said pressure car and said compensating roll, and said compensating lever is pivotally mounted in a stationary bearing intermediate its length.
 5. Apparatus as set forth in claim 4, in which said lever means comprise a connecting lever of adjustable length pivoted to the other end of said compensating lever and to the other of said parts.
 6. Apparatus as set forth in claim 1, in which said support means includes a tension roll for tensioning said felt blanket and pressure-fluid-operable means controlling the tension applied to the felt blanket by said tension roll.
 7. Apparatus as set forth in claim 1, in which said couch-roll means comprise a vacuum couch roll, said vacuum couch roll comprising a stationary hollow shaft for discharging air and water, an outer screening shell rotatably mounted on said shaft, means defining inside said shell a vacuum chamber around part of the inside periphery of said shell, and means for applying a vacuum to said vacuum chamber.
 8. Apparatus as set forth in claim 7, in which said blanket contacts said vacuum couch roll only in part of the periphery thereof and a spraypipe is disposed adjacent to another part of the periphery of said vacuum couch roll and means to supply said spraypipe with liquid to clean said vacuum couch roll.
 9. Apparatus as set forth in claim 8, which comprises means for intermittently supplying said spraypipe with liquid.
 10. Apparatus as set forth in claim, 8 in which said spraypipe extends outside said vacuum couch roll.
 11. Apparatus as set forth in claim 8, in which said spraypipe extends inside said vacuum couch roll.
 12. Apparatus as set forth in claim 8, which comprises gutters disposed inside said vacuum couch roll and serving to collect and discharge said liquid.
 13. Apparatus as set forth in claim 8, which comprises gutters disposed outside said vacuum couch roll and serving to collect and discharge said liquid.
 14. Apparatus as set forth in claim 1, which comprises a covering on said breast roll.
 15. Apparatus as set forth in claim 14, in which said covering consists of plastic material.
 16. Apparatus as set forth in claim 14, in which said covering consists of rubber.
 17. Apparatus as set forth in claim 14, in which said covering consists of a tubular screen of plastic material.
 18. Apparatus as set forth in claim 17, in which said breast roll comprises a body and said screen surrounds said body and is peripherally movable relative thereto.
 19. Apparatus as set forth in claim 1, in which said breast roll consists of a screening roll.
 20. Apparatus as set forth in claim 19, which comprises means for applying subatmospheric pressure to the interior of said breast roll.
 21. Apparatus as set forth in claim 1, which comprises a mandrel-depositing station, a mandrel-winding station comprising said pressure roll means and said breast roll, a calendering station, a mandrel-extracting station, and a manDrel-feeding car, which is movable between said four stations, said mandrel-depositing station comprising means for depositing a mandrel on said car, said calendering station comprising means for calendering said web on a mandrel carried by said car, said mandrel-extracting station comprising means for extracting a mandrel carried by said car from said web wound in tubular form on said mandrel, means for advancing said car by one station when a mandrel has been sufficiently wound with said web in said mandrel-winding station, and for moving said car back by one station when said mandrel has been extracted from said web in said mandrel-extracting station. 